VLAN for Management Traffic

Question

Hello Everyone,
I'm still learning cisco and networks in general but I need to separate management traffic from the regular network.  The switch is a cisco catalyst 5406-E.  My question is do I need to create a new subnet for the VLAN and how would I do that? The commands I have to create a VLAN and add the switch ports are
Switch(config)# vlan 15
switch(config-vlan)# name Management
switch(config)# interface GigabitEthernet2/6
switch(config-if)# switchport access vlan 15
Now this creates vlan 15 and adds the GE 2/6 interface to vlan 15.  How do I add it to a new subnet?  Am I going in the right direction?

Answer 1

In general, if you want to use separated VLAN for management, you can create VLAN + SVI (routed interface of the VLAN) with IP address + some access list on SVI and VTY (“SSH/telnet lines”) for better security.
Example:
==== C4500 – L3 SWITCH CONFIG ====
//create VLAN 15
vlan 15
name MGMT
//create access list with ip addresses, from which management of all switches with SVI 15 will be accessible
//Note: this access list (ACL) does not control access to management of L3 switch/router where the ACL is applied on SVI, only to all other switches in VLAN 15 that have default gateway set to ip address 10.0.15.1 (see next step)
ip access-list extended MGMT_SWITCH
remark ====ICMP====
permit icmp any 10.0.15.0 0.0.0.255
remark ====ADMIN====
permit ip 10.0.1.0 0.0.0.255 10.0.15.0 0.0.0.255
remark ====MONIORING-SERVERS====
permit ip 10.0.100.0 0.0.0.255 10.0.15.0 0.0.0.255
remark ====NTB-SERVICE====
permit ip 10.0.200.0 0.0.0.255 10.0.15.0 0.0.0.255
//create SVI/interface of the VLAN 15, add IP address and assign access list
//Note: DO NOT assign empty access list to interface, it can make your router inaccessible!
interface Vlan15
description MGMT
ip address 10.0.15.1 255.255.255.0
ip access-group MGMT_SWITCH out
//create ACL for VTY line of L3 switch/router; this ACL controls access only to management of L3 switch, access to all other switches with SVI 15 is controlled by previous ACL
ip access-list standard VTY
remark ====ADMIN====
permit 10.0.1.0 0.0.0.255
remark ====MONIORING-SERVERS====
permit 10.0.100.0 0.0.0.255
remark ====NTB-SERVICE====
permit 10.0.200.0 0.0.0.255
//assign ACL to vty lines
line vty 0 4
access-class VTY in
==== OTHER L2-ONLY SWITCHES CONFIG ====
//create VLAN 15
vlan 15
name MGMT
//create SVI 15
interface Vlan15
description MGMT
ip address 10.0.15.50 255.255.255.0
//set default gateway/default route to SVI of c4500
ip default-gateway 10.0.15.1
//some higher-level switches require use of following CLI parameters instead:
ip routing
ip route 0.0.0.0 0.0.0.0 10.0.15.1
This is just one of many ways to do the management separation.